Hey has anybody got the unit 5 notes with the red writing? They were on scribd but can no longer find them. They got me through AS and I have the unit 4 ones but just can't find the unit 5. They are so good I will my A Level in biology to these notes haha

(Original post by Zuzuvela)
Hey has anybody got the unit 5 notes with the red writing? They were on scribd but can no longer find them. They got me through AS and I have the unit 4 ones but just can't find the unit 5. They are so good I will my A Level in biology to these notes haha

Every time I go over them and do exam questions I get the information muddled e.g- if the question is supposedly asking about DNA markers I will misinterpret the question and talk about DNA probes etc. Maybe its just me idk but Im just wondering if there is a way to revise this in enough detail but without getting muddled?

(Original post by Nightinwind)
heya, can anyone explain why when you do a partial digest in restriction mapping the total length of dna fragments obtained adds up to more than length of original dna?!!!

Every time I go over them and do exam questions I get the information muddled e.g- if the question is supposedly asking about DNA markers I will misinterpret the question and talk about DNA probes etc. Maybe its just me idk but Im just wondering if there is a way to revise this in enough detail but without getting muddled?

I have exactly the same problem aha, I've gone over the "DNA Technology Section" at least 10 times in depth but it just isn't going in. Everything is too similar. Anyone got any suggestions on how to get my head round it? Or is it just a case of going through it 1,000,000 times
Anyone got any methods that helped them

(Original post by NapkinofDestiny)
I have exactly the same problem aha, I've gone over the "DNA Technology Section" at least 10 times in depth but it just isn't going in. Everything is too similar. Anyone got any suggestions on how to get my head round it? Or is it just a case of going through it 1,000,000 times
Anyone got any methods that helped them

(Original post by Honeybee3803)
I love biology, but I have to admit PCR is my downfall!

We've been told that it's something you can learn a stock answer for if you're struggling, this is the one I use :
1.) The temperature of the DNA mixture is raised to 95°C to break hydrogen bonds between the DNA strands, separating them.
2.) Primers, free DNA nucleotides, and DNA polymerase are added to the mixture. You must be specific about saying DNA and nucleotides rather than bases. The temp is lowered to 55°C - 60°C. This temperature allows the primers to anneal. Anneal is a keyword! The primers allow DNA polymerase to bind to the single DNA strand.
3.) The temp is raised to 72°C which is optimum for DNA polymerase to form the complementary DNA strand using the template via specific base pairing.
4.) Repeated for as much DNA as you want.
Sometimes they ask about how much DNA is formed after so many cycles, here it's important to remember that a new molecule of DNA will be formed from each single strand present so for example:
One piece of DNA > 2 single strands > two pieces of DNA made > four single strands > 4 pieces of DNA made and so on.
Hopefully this helps a bit

(Original post by pineneedles)
We've been told that it's something you can learn a stock answer for if you're struggling, this is the one I use :
1.) The temperature of the DNA mixture is raised to 95°C to break hydrogen bonds between the DNA strands, separating them.
2.) Primers, free DNA nucleotides, and DNA polymerase are added to the mixture. You must be specific about saying DNA and nucleotides rather than bases. The temp is lowered to 55°C - 60°C. This temperature allows the primers to anneal. Anneal is a keyword! The primers allow DNA polymerase to bind to the single DNA strand.
3.) The temp is raised to 72°C which is optimum for DNA polymerase to form the complementary DNA strand using the template via specific base pairing.
4.) Repeated for as much DNA as you want.
Sometimes they ask about how much DNA is formed after so many cycles, here it's important to remember that a new molecule of DNA will be formed from each single strand present so for example:
One piece of DNA > 2 single strands > two pieces of DNA made > four single strands > 4 pieces of DNA made and so on.
Hopefully this helps a bit

Thank you I have looked at mark schemes for this, and it does seem to be the same step by step answers everytime, I know about the word anneal but the thing I struggle with is remembering the temperatures in the correct order and the reason why they need to be that temperature, i'm okay with what it produces and how the ingredients help that if that makes sense. Its just something I need to write out a few times, thank you though much appreciated

(Original post by NapkinofDestiny)
I have exactly the same problem aha, I've gone over the "DNA Technology Section" at least 10 times in depth but it just isn't going in. Everything is too similar. Anyone got any suggestions on how to get my head round it? Or is it just a case of going through it 1,000,000 times
Anyone got any methods that helped them

I feel like the CGP revision guide (with bad jokes) is pretty okay for getting your head round the very very basics. And then unfortunately it is a case of going over and over the nelson thornes textbook and to be honest, it is a matter of understanding the basics of DNA before you can fully understand the rest. To see if you understand, do some questions and youtube videos are a really good resource too.